Effect of wall thermal conductivity and thickness on the performance of heat-recirculating reactors

Recent studies of spiral counterflow "Swiss-roll" heat-recirculating reactors have demonstrated the importance of streamwise heat conduction on their performance. Titanium-811 Swiss rolls having a thermal conductivity (k) of 6 W/m-K, geometrically similar to inconel-718 reactor (k ≈ 11.4 W/m-K), were constructed to test this hypothesis using propane-air mixtures with speciallyprepared Pt catalyst. Three different wall thicknesses were studied. As suggested by theoretical studies, better performance was found for low-k, thin-walled reactors. Under these conditions, self-sustaining chemical reaction could be maintained at maximum temperatures below 55 °C with ignition temperatures below 90 °C. These results may be useful for development of micropower generation devices employing thermoelectrics or solid-oxide fuel cells.